The code and compilation for me is the light part, and for the most part an hour's worth of essentially text editing for about a moment of compilation anyways.
My resource hogs are slack, mainly the browser, and Zoom calls are apparently the most computationally intensive thing in the world, especially if you screen share while you have an external plugged in.
Memory wise the reason I had to go from 8Gb to 16GB on my personal laptop was literally just for TravisCI.
Honestly, adding external monitors cripples MacBooks pretty quick, even unscaled 2 2k monitors will slow a 2015 15 down significantly (don't try and leave YouTube on either), and it gets worse from there once you start upgrading to 4k monitors. a 2017 15 is good for a 4k and a 2k, and gets a bit slow if you try and go dual 4k.
I planned on looking into eGPU solutions until IT offered me a new Macbook, and I convinced them I needed a 16" Pro.
tldr: External monitors or badly optimized applications (Zoom, YouTube, or browser based CI) will make most MacBooks feel sluggish pretty quick.